Electronic organs have been known in the Patent arts and in the marketplace for several decades. Such organs have generally operated on analog principles with the provision of one tone generator for each note of the organ. It has been common practice to use separate oscillators for each generator, or to provide twelve master oscillators for the top octave or one octave above the top octave with the divide-by-two circuits for producing the remaining octaves of the organ. More recently it has become rather common practice to provide a single high frequency master oscillator and to divide the frequency thereof by parallel dividing circuits of different divider ratios to provide the top octave of notes, such top octave being applied to strings of divide-by-two circuits to provide the gamut of the organ.
Chords can be played manually on the accompaniment keyboard of an organ, either electronic or wind, in accordance with techniques dating far back. Devices have been provided for electronic organs for the playing of chords simply upon depression of single buttons or single keys. In addition, rhythm devices for automatically producing rhythms have been used in electronic organs, and such rhythm devices have been used in conjunction with the playing of chords to play the chord notes sequentially.
More recently efforts have been made to produce electronic organs using digital techniques, including to some degree elimination or minimization of redundancy in the number of tone generators, and in multiplexing of keyboards. Techniques heretofore used in analog electronic organs are not necessarily directly translatable into digital electronic organs.